The Hindustani Classical Music books follow mainly 2 types of Notation system . 1) Bhatkande notation system and 2) Vishnu Digambar System
the Bhatkande system has the following features
1) The shuddha swara - Re Ga Ma Madhya saptak (middle octave) (without any sign)
2) The komal swara - Re Ga Dha Ni
3) Teevra swara - Mal
4) Mandra saptak - Ni.
5) Tar saptak - Dha.